I now feel I have sufficient experience using the HiHy A/C to assess the relative impact on my MPG. When not using the A/C due to moderate weather, I was able to consistently attain abot 30 MPG (suburban environment). Once I started using the A/C all the time I dropped to about 27 MPG driving in the same environment. Looks like the A/C results in about a 10% hit on MPG. This is on a base model HiHy where I manually turn the A/C on and leave it (fan on position 1, recirc on or off depending on the level of cooling required). If the Limited auto A/C cycles the A/C on and off to maintain temperature the impact may be less.

This was not a scientific study, just casual observations. YMMV.

 

I have watched the mpg with AC on and off,But not really to close. I an pretty sure I loose about 2MPG with ac on!!